True, it may seem like possibly, maybe flipping one state legislative chamber doesn’t stack up to those other accomplishments. But more than their implications for governance of Virginia, Tuesday night’s legislative results should cheer Democrats because of what they represent: the best bellwether to date of the 2018 congressional elections.

Ahead of Tuesday, liberals were already rightly bullish about their midterm prospects because of the clear pattern of Democraticoverachievement in special elections for congressional and state legislative seats in 2017. Historically, special-election results, in the aggregate, have been a pretty good omen for how a party will do in the following midterms, but it’s best not to rely too heavily on such a small sample of fickle data points (these elections are, by definition, special). And now with Tuesday’s 100 elections for the Virginia House of Delegates and 40 elections for the New Jersey state Senate, we have more than twice as much legislative-election data as we did coming into the week.1

As FiveThirtyEight contributor David Wasserman has pointed out, these regularly scheduled elections are better approximations of 2018’s U.S. House elections. Unlike special elections, in which unpredictable turnout levels can favor one party and skew the results, Virginia’s and New Jersey’s elections occurred concurrently with those states’ gubernatorial elections (36 states will select a governor in 2018), a pairing that typically leads to more predictable turnout. Perhaps most importantly, these legislative elections were predominantly2 not open-seat races, as vacancy-triggered special elections obviously are. Tuesday was our first chance to see whether Democrats could still beat expectations when going up against the powerful force of incumbency advantage.3

The answer — as we’d expect with actual incumbents on the ballot — is that Democrats did well on Tuesday but didn’t outperform expectations to the degree they have in special elections this year. On average, the party’s candidates for Virginia House of Delegates and New Jersey state Senate won by margins that were 3 percentage points better than their district’s partisan lean.4

How Democrats did in the Virginia House of Delegates

Democratic performance in districts relative to each district’s partisan lean

VOTE SHARE

DISTRICT

DEM.

REP.

DEM. MARGIN IN 2017 ELECTION

PARTISAN LEAN

DIFF

20th

43%

55%

-12

-22

+10

1st

24

76

-52

-61

+9

86th

69

31

+38

+29

+9

2nd

63

37

+26

+18

+8

3rd

22

78

-56

-64

+8

25th

42

58

-16

-24

+8

34th

61

39

+22

+14

+8

42nd

62

38

+24

+16

+8

12th

54

46

+8

+1

+7

38th

74

26

+48

+41

+7

72nd

53

47

+6

-1

+7

27th

50

50

0

-6

+6

33rd

45

55

-10

-16

+6

85th

51

49

+2

-3

+5

93rd

60

40

+20

+15

+5

17th

39

61

-22

-26

+4

21st

53

47

+6

+2

+4

62nd

48

52

-4

-8

+4

81st

41

59

-18

-22

+4

87th

62

38

+24

+20

+4

9th

30

70

-40

-43

+3

10th

52

48

+4

+1

+3

28th

50

50

0

-3

+3

32nd

59

41

+18

+15

+3

49th

81

19

+62

+59

+3

55th

40

60

-20

-23

+3

8th

36

64

-28

-30

+2

31st

54

45

+9

+7

+2

56th

40

60

-20

-22

+2

84th

48

52

-4

-6

+2

26th

45

55

-10

-11

+1

29th

36

64

-28

-29

+1

51st

53

47

+6

+5

+1

59th

34

61

-27

-28

+1

65th

36

64

-28

-29

+1

82nd

41

59

-18

-19

+1

91st

44

56

-12

-13

+1

96th

43

57

-14

-15

+1

23rd

34

66

-32

-32

0

30th

38

62

-24

-24

0

64th

38

62

-24

-24

0

73rd

51

49

+2

+2

0

88th

37

53

-16

-16

0

98th

35

65

-30

-30

0

18th

34

61

-27

-26

-1

7th

34

66

-32

-30

-2

50th

54

46

+8

+10

-2

66th

36

64

-28

-26

-2

68th

50

50

+1

+3

-2

97th

28

72

-44

-42

-2

13th

54

46

+8

+11

-3

83rd

44

56

-12

-9

-3

94th

49

49

0

+3

-3

54th

42

58

-16

-12

-4

67th

58

42

+16

+20

-4

40th

50

50

0

+5

-5

99th

38

62

-24

-19

-5

58th

38

62

-24

-18

-6

100th

47

53

-6

+2

-8

60th

38

62

-24

-14

-10

Only races that pitted one Democrat against one Republican are included. 2017 election results are unofficial and as of 2 a.m. Eastern on Nov. 8.
A district’s “partisan lean” is the average difference between how the district voted and how the country voted overall in the last two presidential elections, with 2016 weighted 75 percent and 2012 weighted 25 percent.

Sources: Associated Press, Daily Kos Elections

How Democrats did in the New Jersey state Senate

Democratic performance in districts relative to each district’s partisan lean

VOTE SHARE

DISTRICT

DEM.

REP.

DEM. MARGIN IN 2017 ELECTION

PARTISAN LEAN

DIFF

1st

65%

34%

+31

-8

+39

33rd

88

12

+76

+54

+22

3rd

59

41

+18

-2

+20

32nd

80

20

+60

+40

+20

27th

69

31

+38

+22

+16

36th

66

34

+32

+17

+15

31st

84

16

+68

+55

+13

30th

40

60

-20

-32

+12

37th

75

25

+50

+38

+12

18th

65

35

+30

+19

+11

20th

83

17

+66

+55

+11

34th

85

15

+70

+60

+10

6th

69

31

+38

+29

+9

29th

87

11

+76

+68

+8

7th

66

34

+32

+25

+7

24th

39

61

-22

-29

+7

38th

57

43

+14

+7

+7

13th

45

55

-10

-15

+5

10th

37

63

-26

-29

+3

22nd

67

33

+34

+31

+3

35th

79

21

+58

+55

+3

5th

65

34

+31

+29

+2

14th

56

44

+12

+10

+2

11th

53

47

+6

+5

+1

12th

41

57

-16

-17

+1

15th

74

26

+48

+47

+1

39th

46

53

-7

-8

+1

17th

71

29

+42

+42

0

25th

48

52

-4

-4

0

26th

43

57

-14

-13

-1

9th

35

65

-30

-27

-3

40th

43

57

-14

-11

-3

23rd

41

59

-18

-14

-4

8th

48

52

-4

+1

-5

21st

45

55

-10

+3

-13

16th

48

52

-4

+10

-14

2nd

46

54

-8

+11

-19

Only races that pitted one Democrat against one Republican are included. 2017 data are unofficial results as of 2 a.m. Eastern on Nov. 8.

Sources: Associated Press, Daily Kos Elections

Unsurprisingly, incumbency was a major factor in how Democrats fared. In open seats and districts with Democratic incumbents, the party outperformed the partisan lean by a healthy amount — although not by the same 14 points by which they beat the partisan lean in special state legislative elections the last time we examined this question.5 But in districts with Republican incumbents, Democrats basically matched the district’s partisan lean.

A blue night

Average Democratic performance relative to each district’s partisan lean, by incumbency status

TYPE OF RACE

VIRGINIA HOUSE OF DELEGATES

NEW JERSEY STATE SENATE

BOTH

Open seats

+5

+8

+6

Seats with Democratic incumbents

+6

+10

+9

Seats with Republican incumbents

+1

-1

0

All seats

+2

+5

+3

Only races that pitted one Democrat against one Republican are included. Results are unofficial and as of 2 a.m. Eastern on Nov. 8.

Sources: Associated Press, Daily Kos Elections

In Virginia specifically, the main reason that Democrats were able to win so many House of Delegates races on Tuesday was that so many Republicans were occupying blue seats. Going by our partisan lean metric, 50 House of Delegates seats are naturally Republican-leaning and 50 are naturally Democratic-leaning; going into Tuesday, Republicans held all 50 of the former and 16 of the latter. If the current leader wins in every race, though, Republicans would hold only two Democratic-leaning seats in the next House of Delegates (Democrats would also hold two Republican-leaning ones). Put another way, Tuesday was a corrective election.6

Basically, the national environment (as expressed by the generic ballot and other indicators) was friendly enough to Democrats that it neutralized Republicans’ incumbency advantage on Tuesday. If this holds in 2018, that may be enough to put the U.S. House in play. And, of course, not all seats Republicans will be defending will feature incumbents, further brightening the outlook for Democrats. The more Republicans continue to retire from Congress, the clearer the Democrats’ path to a House majority will become.

Footnotes

I’m disregarding the 40 elections for New Jersey General Assembly, the state’s lower chamber, that were also held on Tuesday. General Assembly districts elect two legislators each, and all candidates in the district run in the same race; the top two vote-getters are elected. This irregular arrangement makes Assembly races too different from typical elections to make a credible comparison.

130 out of 140.

Which Republicans possessed in 74 of Tuesday’s 140 legislative campaigns and will likely possess in more than 200 of 2018’s 435 U.S. House races.

A district’s “partisan lean” is the average difference between how the district voted and how the country voted overall in the last two presidential elections, with the 2016 results weighted 75 percent and the 2012 results weighted 25 percent. As always, thanks to Daily Kos Elections for calculating the presidential results by legislative district.

This suggests that Democrats owe just as much of their special-election dominance to favorable turnout patterns as to not facing incumbents.

Because we know you’re wondering: In the U.S. House, Republicans occupy 14 seats with a Democratic partisan lean.

Nathaniel Rakich is a politics and baseball writer whose work has also appeared in The New Yorker, The New Republic and The Boston Globe. @baseballot